That's a serious mod during the warranty period, unlike motorcycle dealers car dealers don't usually recommend, its possible you'd void your warranty. Best to talk with knowledgeable shop(s) that do performance mods. A true dual exhaust system requires 2 new header pipes (not sure how CAT comes into play) from the exhaust manifold back. On motorcycIe they remap ECM, on a car its either PCM or ECM. To just add a 2nd muffler the difference is negligible, got to go all the way with 2 headers, tune engine and dyno for optimum torque and HP; cha ching.